Revit compatiblilty

[Archman]

Is Revit Structures 3 and Revit Systems compatible with Revit 8.1, or will I need to upgrade to Revit 9 to "talk" to my engineers?

[christopher.zoog51272]

Is Revit Structures 3 and Revit Systems compatible with Revit 8.1, or will I need to upgrade to Revit 9 to "talk" to my engineers?
You will need to upgrade. RS3 and RSYS1 are based on RB9